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Intrin: Add _umul128 

Implement _umul128; it provides the high and low halves of a 128-bit
multiply.  We can simply use our __int128 arithmetic to implement this,
we generate great code for it:
        movq    %rdx, %rax
        mulq    %rcx
        movq    %rdx, (%r8)
        retq

Differential Revision: http://reviews.llvm.org/D6486

llvm-svn: 223175
This commit is contained in:
David Majnemer 2014-12-02 23:30:24 +00:00
parent 22f58dffeb
commit 5f9afc59f8
1 changed files with 12 additions and 3 deletions
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15
clang/lib/Headers/Intrin.h
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@ -417,9 +417,18 @@ int __cdecl _setjmpex(jmp_buf);
#endif
unsigned __int64 _shlx_u64(unsigned __int64, unsigned int);
unsigned __int64 shrx_u64(unsigned __int64, unsigned int);
unsigned __int64 _umul128(unsigned __int64 _Multiplier,
unsigned __int64 _Multiplicand,
unsigned __int64 *_HighProduct);
/*
* Multiply two 64-bit integers and obtain a 64-bit result.
* The low-half is returned directly and the high half is in an out parameter.
*/
static __inline__ unsigned __int64 __attribute__((__always_inline__, __nodebug__))
_umul128(unsigned __int64 _Multiplier, unsigned __int64 _Multiplicand,
unsigned __int64 *_HighProduct) {
unsigned __int128 _FullProduct =
(unsigned __int128)_Multiplier * (unsigned __int128)_Multiplicand;
*_HighProduct = FullProduct >> 64;
return FullProduct;
}
void __cdecl _xrstor64(void const *, unsigned __int64);
void __cdecl _xsave64(void *, unsigned __int64);
void __cdecl _xsaveopt64(void *, unsigned __int64);